1. Field of the invention
The present invention relates to the treatment of wastewater from an aerobic wastewater treatment plant. More particularly, the present invention relates to a system for disinfecting wastewater from an aerobic wastewater treatment plant using a liquid disinfectant.
2. Description of the prior art
Aerobic wastewater treatment plants are commonly used in the United States in areas where there is a lack of municipal sewerage treatment and disposal. These generally small volume plants, e.g., flow rates of under 5,000 gallons per day, typically comprise an aerobic treatment chamber wherein the sewerage is initially subjected to bacterial action to break down the solids, a clarifier to allow residual solids to be removed from the aerobically digested sewerage to produce treated wastewater, and a discharge system which typically is in the form of a pump tank containing a discharge pump which can be used to discharge the treated water in the pump tank in a variety of ways, e.g., night spray systems, drip irrigation systems, discharge into a stream or the like.
Regardless of the method by which the water is finally discharged, most State and Federal regulations require that the water to be discharged be disinfected to eliminate or at least reduce the bacteria to an acceptable level. For this purpose, it has been common to use chlorinators, particularly chlorinators using tablets or other forms of solid, chlorine generating materials. It is also known to use liquid chlorinators wherein an amount of a liquid chlorine containing composition is injected into the clarified (treated) wastewater.
Typically liquid chlorinators have relied on the use of venturis or venturi-like pumps (venturi systems) to draw the liquid chlorine composition from a storage system into wastewater passing through the venturi system. An inherent problem with these venturi systems is that the wastewater passing there through is generally not totally free of solids. Since typically the nozzles of venturi systems have small diameter openings, there is a likelihood of plugging of the venturi with a concomitant disabling of the liquid chlorine composition infusion system. Examples of typical liquid chlorinators or liquid disinfectant systems employing the aspirating phenomena of venturi systems include U.S. Pat. Nos. 3,996,139; 4,019,983; 6,627,071 and U.S. Patent Application Publication 2003/0155311.